The present invention relates to a structure for mounting a video controller on a processor circuit board, sometimes called a xe2x80x9cmotherboardxe2x80x9d for use in computers, such as personal computers and network workstations. In particular, the invention is directed to a socket adapted to receive a plug-in single-chip video controller, and to a circuit board and computer system containing the socket.
Currently video controllers for use in small computers, such as personal computers and network computers, are connected to a processor motherboard in one of two ways. One is by hard wiring a plurality of video controller integrated circuits (xe2x80x9cchipsxe2x80x9d) and associated video memory directly onto a computer motherboard, and the other is by plugging in a card containing the video controller circuitry and associated memory into a card socket provided on the motherboard.
Currently many, if not most, video controller chip sets directly wired to the motherboard, or video controller cards which plug into a socket on the motherboard, comply with the Intel AGP/PCI interface standard called the Accelerated Graphics Port Interface Specification (Version 1.0, published by Intel, Jul. 31, 1996). This is a high speed specification for a video bus designed to improve video data throughput through a computer system and permits access of the video controller to main system memory for certain video operations.
When a video controller chip set is directly wired onto the motherboard, the motherboard manufacturer chooses the chip set based on its own design criteria which may or may not reflect the needs of the ultimate computer user. Although this provides a relatively low cost video controller implementation, the video controller design is fixed and inflexible. Accordingly, if a user wishes to change, e.g. upgrade, the video controller, it is impossible to do so without changing the motherboard or adding a separate plug-in video controller board to an available PCI bus socket. Replacing the motherboard is both costly and time consuming, and is typically only done by a trained professional. Adding a new video controller board is also costly and, additionally, the PCI bus structure is relatively slow considering today""s video graphics requirements.
In addition, a wired-in video controller chip set also requires additional land patterns on the motherboard to accommodate the several chips which implement the video controller as well as the associated video memory, and to provide additional memory land areas for possible expansion of the video memory.
The plug-in video controller board has advantages over the wired-in chip sets, since the user can easily replace one video controller board, which includes the video chip set and associated video memory, with another. While this allows for ease of modification of the video controller circuitry without requiring replacement of the motherboard, the plug-in video controller board itself is expensive and further it occupies one of the computer system""s accessory sockets which may limit or hamper the ability of the user to plug in other desired circuit cards. Indeed, for those motherboards which accept a plug-in video controller card which is AGP/PCI compliant, a special socket is required just for the video controller board.
The present invention is designed to remedy problems associated with both the wired-in video controller chip set and the plug-in video controller boards. It provides a socket for a motherboard which is adapted to receive a single chip integrated circuit video controller which has embedded video memory and which provides all of the video controller functions currently supplied by existing video controller chip sets or plug-in video card controllers and associated video memory. Preferably the socket and its associated plug-in video controller chip are AGP/PCI compliant.
Providing a socket for receiving a single-chip plug-in video controller on the motherboard allows an OEM computer system manufacturer and/or vendor to easily adapt the computer system to the video requirements of a user by simply choosing the plug-in chip which best fits the user""s requirements. The invention also provides a reduced system cost compared to add-in card video controller implementations and provides for a simplified assembly and testing of a computer system. Likewise, a vendor or user can easily replace one plug-in video controller chip with another for upgrading or if the user""s video requirements otherwise change. This also allows for easy and relatively inexpensive upgradability of the video controller without requiring replacement of a motherboard or a whole card of expensive components. Furthermore, using a single chip video controller permits the computer system to obtain a higher speed video performance with reduced power consumption because of the embedded memory within the video controller chip.
Accordingly, the invention provides a plug-in single chip video controller socket for use on a motherboard and a motherboard and computer system containing the socket. The socket is wired on the motherboard and is electrically connected with the other board components which make up a computer system, including a microprocessor, main memory circuits, input/output ports etc. The socket has receiving terminals for the pins of the video controller chip and electrical solder terminals for connecting the pins of the video controller chip with the other circuits on the motherboard. The socket also provides connections between the video controller chip and video input and output terminals also provided on the motherboard. A computer system circuit board is thus provided which allows for an easy choice of video controllers to be used with the computer system, while at the same time freeing up board real estate normally reserved for the video chip sets and associated video memory and/or for a socket for a plug-in video controller card.
Preferably, the socket and motherboard containing it are compliant with Intel AGP/PCI specifications as well as the VESA VIP specifications for video input.
These and other advantages and features of the invention will be more readily understood from the following detailed description of the invention, which is provided in connection with the accompanying drawings.